package com.novel.service.impl;

import com.novel.dto.Result;
import com.novel.entity.VoucherOrder;
import com.novel.mapper.VoucherOrderMapper;
import com.novel.service.ISeckillVoucherService;
import com.novel.service.IVoucherOrderService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.novel.utils.RedisIdWorker;
import com.novel.utils.UserHolder;
import org.redisson.api.RedissonClient;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.Resource;
import java.util.Collections;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
public class VoucherOrderServiceImpl extends ServiceImpl<VoucherOrderMapper, VoucherOrder> implements IVoucherOrderService {

    @Resource
    private ISeckillVoucherService seckillVoucherService;

    @Resource
    private RedisIdWorker redisIdWorker;

    @Resource
    private StringRedisTemplate stringRedisTemplate;

    @Resource
    private RedissonClient redissonClient;

    private static final DefaultRedisScript<Long> STOCK_SCRIPT;
    static {
        STOCK_SCRIPT = new DefaultRedisScript<>();
        STOCK_SCRIPT.setLocation(new ClassPathResource("seckill.lua"));
        STOCK_SCRIPT.setResultType(Long.class);
    }

    @Override
    public Result seckillVoucher(Long voucherId) {
        //获取用户
        Long userId = UserHolder.getUser().getId();
        //执行lua脚本
        Long result = stringRedisTemplate.execute(
                STOCK_SCRIPT,
                Collections.emptyList(),
                voucherId.toString(), userId.toString()
        );
        //判断结果是否为0
        int r = result.intValue();
        if(r != 0){
            //没有购买资格
            return Result.fail(r == 1 ? "库存不足":"不能重复下单");
        }
        long orderId = redisIdWorker.nextId("order");
        //TODO 保存阻塞队列

        //返回订单id
        return Result.ok(orderId);
    }

    /*@Override
    public Result seckillVoucher(Long voucherId) {
        //查询优惠券
        SeckillVoucher voucher = seckillVoucherService.getById(voucherId);
        //判断秒杀是否开始
        if (voucher.getBeginTime().isAfter(LocalDateTime.now())) {
            //尚未开始
            return Result.fail("秒杀尚未开始");
        }
        //判断秒杀是否结束
        if (voucher.getEndTime().isBefore(LocalDateTime.now())) {
            //秒杀结束了
            return Result.fail("秒杀已经结束");
        }
        //判断库存是否充足
        if (voucher.getStock() < 1) {
            //库存不够了
            return Result.fail("库存不足");
        }

        long userId = UserHolder.getUser().getId();
        //创建锁对象
        //SimpleRedisLock lock = new SimpleRedisLock("order:" + userId, stringRedisTemplate);
        RLock lock = redissonClient.getLock("order:" + userId);
        //获取锁
        boolean isLock = lock.tryLock();
        //判断是否获取锁
        if (!isLock) {
            //获取锁失败，返回错误或重试
            return Result.fail("不允许重复下单");
        }
        try {
            //获取代理对象
            IVoucherOrderService proxy = (IVoucherOrderService)AopContext.currentProxy();
            return proxy.createVoucherOrder(voucherId);
        } finally {
            //释放锁
            lock.unlock();
        }
    }*/

    @Transactional
    public Result createVoucherOrder(Long voucherId){
        //一人一单
        long userId = UserHolder.getUser().getId();
        //查询订单
        int count = query().eq("user_id", userId).eq("voucher_id", voucherId).count();
        if(count>0){
            return Result.fail("用户已经购买一次了");
        }
        //扣减库存
        boolean success = seckillVoucherService.update().setSql("stock = stock - 1")
                .eq("voucher_id", voucherId)
                .gt("stock",0)
                .update();
        if (!success) {
            return Result.fail("库存不足");
        }
        //创建订单
        VoucherOrder voucherOrder = new VoucherOrder();
        long orderId = redisIdWorker.nextId("order");
        voucherOrder.setId(orderId);
        voucherOrder.setUserId(userId);
        voucherOrder.setVoucherId(voucherId);
        save(voucherOrder);
        //返回订单id
        return Result.ok(orderId);
    }
}
